Adverse effect of obesity and dysglycemia on bone microarchitecture and strength in youth: sex-related differences.

CONTEXT: The relationship between obesity, type 2 diabetes (T2D), and bone health in youth is not clear.

OBJECTIVE

This work aimed to examine the relationship of adiposity and glucose metabolism with bone mineral content (BMC) and quality (microarchitecture and strength) in youth across the glycemia spectrum, and evaluate sex-related differences.

METHODS

This cross-sectional study was conducted at a research center. Participants included 92 adolescents (56 females); 32% normal weight (NW), 29% overweight-normal glucose tolerance (OW-NGT), 39% OW-impaired glucose regulation (OW-IGR), including prediabetes (n = 9) or T2D (n = 27). Main outcome measures included bone quality (high-resolution peripheral quantitative computed tomography), body composition and BMC (dual-energy x-ray absorptiometry), anthropometrics, oral glucose tolerance test with glucose and insulin indices, vitamin D and calcium metabolism.

RESULTS

BMC and distal tibia bone microarchitecture and strength (modulus) measures were worse in OW-IGR and OW-NGT compared with NW in males but not in females. In multivariable models, accounting for age, Tanner stage and sex, age, and lean mass (β = 3.9; P < .001) positively, while height (β = -4.5, P < .001) and HOMA-IR (β = -4.6; P = .005) negatively contributed to the variance in tibial volumetric BMD (vBMD) (R2 = 0.45; P < .001). Similar relationships were found with radial vBMD and with whole-bone modulus at the tibia and radius independent of sex. Fasting glucose was inversely related to trabecular thickness at the tibia and radius.

CONCLUSION

There is a negative relationship between adiposity and insulin resistance with bone microarchitecture and strength in youth after accounting for age, sex, height, and lean mass. There appears to be sexual dimorphism in these relationships, with more negative effect of adiposity and dysglycemia on bone quality in males.